Hydraulic bumper jack



Dec. 4,

Filed March 13, 1947 Tla- H. E. PAGE 2,577,539

HYDRAULIC BUMPER JACK 2 SHEETS-SHEET l /feafer E 72455.

BY I ATTQRNE Dec. 4, 1951 E. PAGE 2,577,539

HYDRAULIC BUMPER JACK 2 SHEETS- SHEET 2 Filed March 13, 1947 INVENTOR Aff-afer E .Z3/16s BY ATToRNE Patented Dec. 4, A1951 UN ITED kS TATY orties 2,577,539 HYDRAULIC BUMPER vJACK Herbert E. Page, Dayton, Ohio Application March 13, 1947, Serial No. '734,464 4 claims. (c1. (io-52) This invention relates to a hydraulic jack. It has special application to hydraulic bumper 4jacks.

An object of the invention is to obtain a bumper jack which will be low in collapsed height and yet will have sufcient lift to raise the modern car from the ground. This is of particular value in connection with cars embodying knee Vaction on thefront end, requiring a greater lift Vjack with all operating parts contained Ain the 'base Ybody and with an integrally formed reservoir avoiding the necessity of embodying a special reservoir at the top of the jack. A feature of the jack, as so characterized, is that it may be used -as an extension device by applying the load directly to the top cap.

Other objects and structural details of the invention will appear from the following descripltion when read in connection with the accompanying drawings wherein:

Fig. l is a view, in vertical longitudinal section, of a bumper jack embodying the present invention, and is taken substantially along the line I-I of Fig. 2;

Fig. 2 is a top plan view of the jack of Fig. l;

Fig. 3 is a detailed view of the base section of the jack, in vertical longitudinal section, and taken substantially along the line 3--3 of Fig. 4;

Fig. 4 is a View in vertical .cross section taken substantially along the line 4 4 oi Fig. l;

Fig. 5 is a view of the base section of the jack in rear elevation;

Fig. 6 is a detailed fragmentary view in vertical longitudinal section, showing a modified apparatus for operating the pumping piston of the jack;

Fig. 7 is a view similar to Fig. 6 showing another form of pumping piston operating means; and

Fig. 8 is a view in rear elevation of the device of Fig. '7.

Referring to the drawings, in the embodiment of Figs. 1 to 5 inclusive, a hydraulic jack comprises a base l receiving one end of an outer 'reservoir tube 2, the tube 2 being iixed to base I,

as 'by welding or the like. A tube 3 surrounds tube 2 in contacting relation therewith and supports near Vits upper or outer end a pair of adjustable clamps l and 4b. The clamps 4 and tb 'are arranged in opposed relation, being adapted to grip therebetween a bumper E. The clamps A land llbare provided with handles 4a and tc respectively, the construction and arrangement of the parts being in that respect a conventional one to effect adjustment of the clamps along theV length of tube 3.

A ram sleeve 5 is screwed into the base I at its lower end and receives at its upper or outer end, `with a threaded connection, a bushing B. VRam "sleeve 5 is inwardly spaced from tube 2, while bushing S is anged to engage the outer end of tube?. Within ram sleeve 5 and .spaced therefrom is a piston rod l slidably mounted in bushing 6. rihe lower end of piston rod 'I has a spacer 8 and a cup washer 'S xed thereto. At its upper or outer end, piston rod 'i carries a cap II, fixed to the rod by means of a screw stud ill. 'The'periphery of cap Ii is threaded for attachment to the upper endof tube the assembly comprising tube 3, cap Il, rod l, spacer 8 and washer S being thus connected for motion as a unit.

lAlt' the base, the jack supports a foot operated lever or .treadle I2, pivotally mounted on a rod The lever I2 'is formed with -a pair of rside arms embracing the base of the jack, which arms are connected at the end .adjacent rod I3 by a web I2a, and which at `the front of the jack terminate in a serrated por- Ition 12b. Carried at the rear of the lever I2, beneath the web i211., is a roller HI adapted to engage the closedyprojecting end of a piston l5 reciprocable within pa cylinder 25 formed within thebody I. Referring particularly to Fig. 3, a spring I6 is arranged within cylinder .25 `and 4presses piston .I5 outwardly ,into contact with roller I4.

'The .space between the ram piston rod '"3 and the sleeve '5 ,andy between ram ksleeve `5. and tube 2 are respectivelyidentied as chambers 'il .and i3. and comprise Ythe 'reservoir of the jack,

these spaces being normally filled with a hydraulic liquid. A port I9 near the upper end of :sleeve i5 connects the reservoir chambers il and t8. kAnother port 2i? (Fig. 4) connects the reservoir chamber I8 to a chamber `2i within body I. `which latter chamber is referred vto for reasons which will hereinafter'appear as the high pres-- sure relief and lowering valve chamber. Cornmunicating passages 22 and 24 in body I connect chamber 2| to cylinder 25 within which piston I5 reciprocates. 22 and 24 is arranged to close toward chamber 2|. A port 26 also is provided connecting cylinder 25 to chamber 2|. A poppet valve 28 within port 26 is arranged to close in the direction of cylinder 25 and is urged to closed position by a relatively heavy spring 21. A further port 29 (Fig. 1) is provided connecting cylinder 25 to a chamber 36, another port 3| leading from chamber 38 to a chamber 32 beneath the ram piston assembly comprising spacer 8 and washer 9. A poppet valve 34 in port 29 is arranged to close toward cylinder 25 and is pressed to closed position by a relatively light spring 33. A light spring 35 acts on poppet 23 to urge this valve closed.

Arranged between and supported by the side rails of the treadle I2 is a lever 36 pivotally mounted on a cross pin 31. A spring 36a tensioned between pedal portion |2b and a forwardly extending iinger of lever 36, urges the lever in a clockwise direction as viewed in Fig. 1 to place a transverse portion 36h thereof slightly above the level of pedal |212'. Further, a vertical extension 38 of lever 36 is normally aligned with an upstanding lug 39 integral with base I. The arrangement is such that if treadle I2 is depressed without rocking lever 36 from its position shown in Fig. 1, projection 38 will contact lug 39 and so limit downward movement of the treadle and correspondingly limit the extent of inward motion imparted to piston I5. Should the foot of theV operator be so placed as to depress and rock lever 36 at the same time treadle I2 is depressed, projecting portion 38 will have moved out of alignment with lug 39 and an additional motion thereby permitted treadle I2 and piston I5.

The operation of the jack is as follows. Starting from the position shown in Fig. 1, wherein treadle I2 is shown in a lower depressed position, the spring I6 acting on piston I5 will serve, when foot pressure is removed from pedal I2b, to push roller I4 outward, and cause treadle I2 to rock about pivot I3 and rise to the position shown in dotted lines in Fig. 1. When the piston I5 moves to the right, it will draw hydraulic fluid from the reservoir chamber I8, the fluid passing through port and through chamber 2| and port 22 past ball valve 23 into cylinder 25. If the treadle I2 is again depressed it will cause the piston I5 to be moved inward within cylinder 25, and, since the ball valve 23 will now be seated by spring 35, the oil trapped in the cylinder 25 will be forced out the port 29 past poppet valve 34 and through port 3| into chamber 32. Repeated operation of the piston I5 in this manner forces additional fluid into chamber 32, compelling piston 'I and the parts connected thereto to rise.

It will be noted that the pressure developed in the cylinder 25 by pumping action of piston I5 will also act through the port 26 against the poppet valve 28. Since the spring 21 acting on valve 28 is much heavier than the spring 33 acting on valve 34, valve 28 will not be unseated by the pressure of the oil during normal operation of the jack. However, if the jack is overloaded and the pressure within the cylinder 25 becomes excessive then the spring 21 will allow the poppet 28 to move off its seat in port 26 and allow oil to iiow therethrough into chamber 2 I and port 20 back to the reservoir chamber I8. There is thus A check valve 23 between passages provided an overload safety limit which may be made variable by adjustment and selection of the spring 21.

It will further be noted that as the piston assembly on the lower end of rod 1 rises, fluid is caused to iiow from reservoir chamber I1 to chamber I8 to replenish the supply which has been withdrawn from chamber I8 in order to raise the jack.

When it is desired to lower the jack, the operator depresses lever 36 as a part of the same action by which he presses treadle I2 downward, thus causing projection 38 on lever 3E to avoid engagement with projection 39 and allowing roller I4 to move farther to the left in acting on piston I5 than is possible during the normal pumping stroke. This additional motion of lever I2 and roller I4 causes piston I5 to move approximately its full distance into cylinder 25 during which motion it engages a projection 28a on poppet valve 28. Acting through projection 28a., poppet valve 28 is positively forced from its seat. At the same time, piston I5 engages a similar projection 34a. on poppet valve 34 and likewise moves this valve from its seat in port 29. While treadle I2 is held depressed and poppet valves 28 and 34 so held from their seats, hydraulic uid flows from the pressure chamber 32 through port 3| and chamber 30 past poppet valve 34 into cylinder 25 wherefrom it may escape through port 26 past poppet valve 28 into chamber 2| and reach the reservoir chamber I8 through port 20. The release of pressure in chamber 32 allows the extensible ram assembly to descend under load to its normal position.

In Fig. 6 another device is shown for moving the pumping piston I5 farther to the left than during its normal pumping motion in order to lower the jack. In this instance, an eccentric fulcrum 40 is utilized for mounting lever I2, a handle 4I being attached to the eccentric connection. With a limited movement of the lever I2 about pivot 40 the piston contacting roller or rod I4a may be caused to assume different initial starting positions. Thus, moving the handle 4| from the dotted line position to that shown in full lines will enable the piston I5 to be moved farther to the left with the same extent of movement of the treadle I2.

Figs. 7 and 8 show a somewhat similar arrangement except that in this embodiment the handle 4I is replaced by an added foot pedal 42, normally held upward by a spring 43 but which may be depressed as a part of the same motion by which treadle I2 is depressed. An eccentric fulcrum 44 will operate to give piston actuating roller |422 an additional travel sufficient to elect a full inward movement of piston I5 and lowering of the jack.

What is claimed is:

1. In a hydraulic jack incorporating a liquid reservoir and a movable ram, a body, means in said body defining in conjunction with said ram a pressure chamber, a cylinder in said body, a piston reciprocable in said cylinder, first and second passages providing communication respectively between said reservoir and said cylinder and between said cylinder and said pressure chamber, a third passage between said cylinder and said reservoir, a valve in the rst passageway seating toward said reservoir, spring loaded valves in said second and third passages seating toward said cylinder, means defining a normal travel for said piston in said cylinder, and means responsive to an overtravel of said piston for moving said spring loaded valves from their seats.

2. A hydraulic jack according to claim 1, characterized in that said last named means includes projections on said valves extending into said cylinder in position to be engaged by said piston during said overtravel thereof.

3. In a hydraulic jack incorporating a liquid reservoir and a movable ram, a body, means in said body defining in conjunction with said ram a pressure chamber, a cylinder in said body, a piston reciprocable in said cylinder, valve controller means for supplying said cylinder with liquid from the reservoir, a passage leading from said cylinder to said pressure chamber and another passage leading from said cylinder to the reservoir, spring loaded poppet valves in said passages closing toward said cylinder, and projections on said valves extending into said cylinder into cooperative relation with said piston, said piston being capable of a pumping motion without engagement with said projections and being adapted for an additional motion in one direction when it is desired to lower the jack during which added motion it engages said projections and moves said valves from their seats.

4. A hydraulic jack according to claim 3, characterized by operating means for said piston comprising an actuating lever, means dening a normal range of movement for said actuating lever, and means for causing said lever to operate in another range of movement in which it may impart said additional motion to said piston.

HERBERT E. PAGE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

